Answer
Global Warming Potential (GWP) measures how much heat a greenhouse gas (GHG) traps in the atmosphere over a specific time horizon (typically 100 years, GWP100) relative to Carbon Dioxide (CO2).
- Baseline: Carbon Dioxide (CO2) has a baseline GWP = 1.
- Key Marine GHGs & Refrigerants:
- Methane (CH_4): GWP100 approx 28-30 (crucial when evaluating methane slip in dual-fuel engines).
- Nitrous Oxide (N2O): GWP100 265-298.
- R-134a: GWP approx 1,430.
- R-404A: GWP approx 3,922.
- Ammonia (NH3 / R-717): GWP = 0.
- Regulatory Relevance: Essential for calculating EEDI, EEXI, CII, and Lifecycle GHG Intensity (Well-to-Wake) under IMO MARPOL Annex VI regulations and GHG strategies.